1. Field of the Invention
The present invention relates to devices for varying the pneumatic output to a pneumatically driven device, and more particularly, to a variable pneumatic output device for use with pneumatically operated ophthmalic micro-surgical instruments.
2. Description of the Art
Ophthmalic micro-surgical procedures require extraordinarily minute instruments. Furthermore, the fragility and importance of the eye demands that these instruments be extremely accurate and controllable.
Means and methods ot satisfy these requirements are continuously being tested. Significant difficulties exist in perfecting instruments utilizing direct mechanical operation because of the extremely small sizes involved. Similarly, instruments driven electronically or electromechanically are sometimes problematic because of these size limitations.
An alternative and increasingly widely used driving method is the use of pneumatic power. The simplicity of structure and operation makes this method particularly suitable for micro-surgery.
However, difficulties still exist in pneumatic drive systems because of the small scale, relatively low air pressures and small orifices and channels required. This necessitates extremely accurate and closely controllable regulation of air input into the instrument.
Various methods of producing accurate, controllable, yet variable pneumatic pressure for ophthmalic surgery instruments are currently used in the art. However, there is need for improvement in control of the variability of pressure supplied to them.
It is therefore a principal object of the invention to provide a variable pneumatic output device which improves over, and solves many of the problems and deficiencies in the art caused by imprecision of prior control devices.
A further object of the invention is to provide a variable pneumtic output device which provides an accurate, controlled, yet variable pneumatic pressure output for use by an pneumatically driven ophthmalic micro-surgical instrument.
Another object of the invention is to provide a variable pneumatic output device which is controllable by the electronic control means and circuitry of an ophthmalic micro-surgery system.
A further object of the invention is to provide a variable pneumatic output device which is adjustable between and including a minimum fully closed level and a maximum fully open level with precision and accuracy.
Another object of the invention is to provide a variable output pneumatic device which provides a variable pneumatic output virtually instantaneously with the instructions from the control circuitry.
A further object of the invention is to provide a variable pneumatic output device which is reliable, simple in structure, durable, accurate, and economical.
Another object of the invention is to provide a variable pneumatic output device which does not require extensive calibration and maintenance.
These and other objects, features, and advantages of the invention will become apparent with reference to the accompanying drawings and specification.